The present invention relates to a method of manufacturing a linear motor suitably used for a driving power source for a stage holding a substrate in a projection exposure apparatus used in, for example, semiconductor manufacturing steps; a linear motor; a stage apparatus equipped with the linear motor; and an exposure apparatus.
In a photolithography step which occupies an important place in manufacturing steps for manufacturing devices such as semiconductor devices and liquid crystal devices, a projection exposure apparatus has been heretofore employed, which projects and exposes via a projection optical system a circuit pattern of a photomask or a reticle (hereinafter simply referred to as a reticle) onto a substrate such as a wafer and a glass plate on which photosensitive agent is coated. Recently, as the integration density of the semiconductor integrated circuits continues to increase, a reduction projection type exposure apparatus, called a stepper, adopting a step and repeat system has been the primary projection exposure apparatus. The reduction projection type exposure apparatus sequentially projects and transfers a pattern onto a plurality of exposure areas on a substrate while sequentially moving the substrate.
In such a stepper, every time a projection and a transfer are performed while sequentially moving a substrate, the substrate needs to be positioned precisely. Accordingly, a stage for holding, moving, and positioning the substrate is provided. The stage, in which a movable stage making it possible to move the held substrate at least in two directions is provided, and a translatory driving mechanism is in heavy usage as a driving power source for the movable stage.
The translatory driving mechanism includes one which converts a rotary motion to a translatory motion by use of a rotary motor, and another using a translatory type linear motor. Particularly, because the linear motor has a simple structure, a small number of parts, and offers low frictional resistance, the linear motor has come to be a principle driving power source for a mechanism which must perform precise positioning.
The linear motor is composed of a permanent magnet unit and an armature coil unit, which allows the permanent magnet unit and the armature coil unit to move relative to each other, thus generating a propulsive force.
As shown in FIG. 13, there has been heretofore an armature coil unit 2 of a linear motor 1, which has a structure in which a plurality of coil bodies 3 are arrayed.
Each of the coil bodies 3 is constructed by winding up a wire into an almost rectangular shape when viewed sideways, and has an opening portion 3a in its central portion. The plurality of coil bodies 3 are positioned relative to a fitting plate 4 by inserting each opening portion 3a into corresponding one of the protrusions 4a formed so as to correspond to each opening portion 3a. 
Also a technology to achieve high performance of the linear motor by increasing the occupation rate (density) of the armature coil unit for a magnetic gap of the permanent magnet unit has been recently proposed. For example, in the technology disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 8-168229, a linear motor using a flat coil is proposed.
As shown in FIG. 14A, a linear motor 5 proposed in the above publication is schematically constituted by permanent magnets 7 and 7 held by a magnet frame 6 so as to face each other with a predetermined interval therebetween, and an armature coil unit 8 disposed between the permanent magnets 7 and 7. The armature coil unit 8 has a constitution in which flat-shaped coils 9 adheres to both planes of a fitting plate 8a. As shown in FIG. 14B, each coil 9 is formed to be flat-shaped by bending spirally a band-shaped coil which is wound into a rectangle or a parallelogram having a long side. Each coil 9 is positioned by a pin 8b provided on a fitting plate 8a. 
However, in the foregoing conventional linear motor 1 shown in FIG. 13, the following problems exist.
First, in the linear motor 1 shown in FIG. 13, the positioning precision of each coil body 3 in the array direction of the plurality of coil bodies 3 is important. Specifically, as shown in FIG. 15, when there are external shape dimension errors among the coil bodies 3, an array interval of the plurality of coil bodies 3 arrayed deviates relatively from an array interval of the permanent magnets 7 with an accumulation of the errors. When there is an error between the array interval of the permanent magnets 7 and the array interval of the coil bodies 3, unevenness occurs in a propulsive force generated in the linear motor 1, thus influencing performance of the linear motor 1. As a countermeasure for this, though the external dimension precision of each coil body 3 must be increased, the increase in the external dimension precision results in an increase in the coil manufacturing cost.
In addition, in the linear motor 1 shown in FIG. 13, since the opening portion 3a is formed in each coil body 3, the occupation rate (density) of the coil body 3 for a magnetic gap of the permanent magnet unit is lowered in the opening portion 3a. As a result, there is the problem that an efficiency of the linear motor 1 is lowered.
On the other hand, in the linear motor 5 shown in FIG. 14, since the coil 9 equivalent to one phase is wound all in one, the problem owing to the deviation of the array interval created in the linear motor 1 shown in FIG. 13 can be avoided. However, in the linear motor 5 shown in FIG. 14, the fitting plate 8a as well as the coil 9 are interposed between the permanent magnets 7 and 7, and the occupation rate of the coil 9 for the magnetic gap of the permanent magnets 7 and 7 is lowered by the fitting plate 8a, so that efficiency of the linear motor 1 is still influenced. In addition, there is also the problem that such a coil 9 requires a large scale winding apparatus for manufacturing it.
The present invention was made considering the above described circumstances, and the subject of the present invention is to provide a method of manufacturing a linear motor capable of exerting high and stable performance, a linear motor, a stage apparatus equipped with the linear motor, and an exposure apparatus.
The invention according to a first aspect is a linear motor (R1) for allowing a movable body to move by its electromagnetic force, the linear motor (R1) comprising an armature coil (23), wherein the armature coil (23) comprises a plurality of coil bodies (25) and a frame (24) for holding these coil bodies (25) so as to array the coil bodies in one direction, and a positioning portion (28) for holding an end of each coil body (25) at a determined interval along the one direction formed in the frame (24).
With such a structure, the end of each coil body (25) is held by a groove (28) formed in the frame (24), whereby the plurality of coil bodies (25) are positioned at a determined interval.
In the linear motor (R1) described in the first aspect, the invention of a second aspect is characterized in that a notch (31) for passing a wire (C) of each coil body (25) therethrough is formed in the frame (24), and each coil body (25) is connected to one another in the outside of the frame (24).
As described above, the wire (C) of the coil body (25) is drawn out from the notch (31) to the outside of the frame (24), whereby connections of the coil bodies (25) of the same phase can be made outside the frame (24).
In the linear motor (R1) of the second aspect, the present invention of a third aspect of the present invention is characterized in that the notch (31) is formed so as to correspond to the positioning portion (28) formed in the frame (24), and a wire (C) from the end of the coil body (25) held by the positioning portion (28) is passed therethrough.
With such a structure, the notch (31) is formed for each coil body (25).
In the linear motor (R2) of the first to third aspects, the invention of a fourth aspect of the present invention is characterized in that a step portion (38) for holding the plurality of coil bodies (25, 25xe2x80x2) so as to superimpose them thereon is formed in the positioning portion (28, 28xe2x80x2).
With such a structure, the coil bodies (25, 25xe2x80x2) plurally layered can be held by one frame (34).
In the linear motor (R3) of the first to fourth aspects, the invention of a fifth aspect is characterized in that the armature coil (43) is formed by gluing the plurality of frames (24) to each other.
Thus, with regard to the armature coil (43), the plurality of coil bodies (25) held by each frame (24) are constituted by superimposing them.
In the linear motor (R1) of the first to fifth aspects, the invention of a sixth aspect is characterized in that the coil body (25) has a flat polygon shape.
By forming the coil body (25) to the flat shape as described above, it is possible to increase an occupation rate of the armature coil (23) in a gap of a permanent magnet (22).
In the linear motor (R4) of the first to sixth aspects, the invention according of a seventh aspect of the present invention is characterized in that the coil body (55) has a shape obtained by performing winding that is almost cylindrical.
As described above, by holding the coil body (55) having the shape obtained by performing the winding that is almost cylindrical to the groove (58) formed in the frame (54), the same effect as those described above can be obtained also in the coil body (55) having the shape obtained by performing the winding so as to be almost cylindrical, that is, in the conventional type coil body (55).
In the linear motor (R1) of the first to seventh aspects, the invention of the eighth aspect is characterized in that the frame (24) has a pair of holding portions (26) extending along the one direction so as to be apart from each other by a predetermined interval, and the connection portion (27) for connecting these holding portions (26) to each other in both ends thereof, and the plurality of grooves (28) are formed in each of the holding portions (26) at an interval corresponding to the array interval of the permanent magnets (22).
With such a structure, the coil body (25) is held between the pair of holding portions (26). Moreover, by disposing the holding portion (26) at the position which does not interfere with the magnetic force line of the permanent magnets (22), only for the coil body (25) exists between the permanent magnets (22).
In the linear motor of the first to eighth aspects, the invention of a ninth aspect is characterized in that among constituent components constituting the coil fixing frame (70) for holding the armature coil (23), the can (71) for forming a coolant path to cool the coil body (25), and the armature coil (23), all of the constituent components except for the coil body (25) are formed of ceramics, engineering plastic or austenite stainless steel.
The invention of a tenth aspect is a linear motor (R1) which allows a movable body to move by an electromagnetic force, the linear motor comprising: an armature coil unit (23) having a plurality of coil bodies (25) and a frame-shaped holding member (24) for holding these coil bodies (25) so as to array the coil bodies (25).
With such a structure, the plurality of coil bodies (25) are positioned with respect to the holding member (24) with a high precision.
In the linear motor (R1) of the tenth aspect, the invention of a eleventh aspect is characterized in that the holding member (24) holds the plurality of coil bodies (25) along a predetermined direction.
Thus, the plurality of coil bodies (25) are positioned with respect to the holding member (24) along the predetermined direction with a high precision.
In the linear motor (R1) of the tenth aspect, the invention of a twelfth aspect is characterized in that the holding member (24) has positioning portions (28) formed at a predetermined interval to position the plurality of coil bodies (25).
With such a structure, the plurality of coil bodies (25) are positioned with respect to the holding member (24) at a predetermined interval with a high precision.
In the linear motor (R1) of the twelfth aspect, the invention of a thirteenth aspect is characterized in that the positioning portions (28) of the holding member (24) are formed so as to conform to a shape of an end of each of the plurality of coil bodies (25).
Thus, the plurality of coil bodies (25) are positioned with respect to the holding member (24) at a predetermined interval with a high precision, only by allowing an end of the coil body (25) to be held to the positioning portions (28) formed in the holding member (24).
In the linear motor (R1) of the twelfth aspect, the invention of a fourteenth aspect is characterized in that the positioning portions (28) of the holding member are formed by providing the convex portions (29) at a predetermined interval.
With such a structure, the plurality of coil bodies (25) are positioned with respect to the holding member (24) at a predetermined interval with a high precision, only by allowing an end of the coil body (25) to be held to the positioning portion (28) formed between the convex portions (29).
In the linear motor of the tenth aspect, the invention of a fifteenth aspect is characterized in that in the holding member (24), a notch portion (31) for allowing electric lines to pass therethrough from the plurality of coil bodies (25) is formed.
As described above, by drawing out a wire of the coil body (25) outside the holding member (24) from the notch (31), the coil bodies (25) of the same phase can be connected to each other outside the holding member (24), and wiring can be performed in an orderly manner.
In the linear motor of the tenth aspect, the invention of a sixteenth aspect is characterized in that parts constituting the armature coil unit (23) are partially formed of nonmagnetic and nonconductive materials.
Since these materials have high strengths and small coefficients of linear thermal expansion, deformations that accompany temperature change can be prevented. As a result, the invention can contribute to the stabilization of the performance of the linear motor (R1).
In the linear motor of the sixteenth aspect, the invention of a seventh aspect is characterized in that parts constituting a cooling mechanism for cooling the armature coil unit (23) are partially formed of nonmagnetic and nonconductive materials.
Since these materials have high strengths and small coefficients of linear thermal expansion, the deformations that accompany with a temperature change can be prevented. As a result, the invention can contribute to the stabilization of the performance of the linear motor (R1).
The invention of a eighteenth aspect is a stage mechanism (10) which comprises the linear motor (R1) of the tenth aspect.
With such a structure, in the stage mechanism (10), the linear motor (R1) in which the plurality of coil bodies (25) are positioned with respect to the holding member (24) with a high precision can be provided.
The invention of a nineteenth aspect is an exposure apparatus which comprises the linear motor (R1) of the tenth aspect.
Thus, in the exposure apparatus, the linear motor (R1) in which the plurality of coil bodies (25) are positioned with respect to the holding member (24) with a high precision can be provided.
The invention of a twentieth aspect is a method of manufacturing a linear motor, wherein the armature coil unit (26) is formed by holding the plurality of coil bodies (25) by the frame-shaped holding member (24).
Thus, the linear motor (R1) in which the plurality of coil bodies (25) are positioned with respect to the holding member (24) with a high precision can be provided.